Temperature-Dependent Safety Valve for Pyrotechnic Gas Generators
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Solution Overview
Problem
Occupant protection devices with pyrotechnic gas generators face challenges in ensuring safety during vehicle fires, as high temperatures can lead to unintended gas generator activation and potential injury to occupants, and existing solutions may burst due to fire-related pressure increases.
Innovation Solution
Incorporating a temperature-dependent safety valve that opens when a predetermined temperature is exceeded, allowing gases to escape externally, and using a closure element that maintains gas-tight sealing until its material limit temperature is reached, thereby preventing accidental gas release during normal operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a pyrotechnic gas generator is used in occupant protection devices, then the device can provide rapid protection in accidents, but the device risks bursting due to fire-related pressure increases
Solution Approach 1:
A temperature-dependent safety valve is introduced as an intermediary component between the gas generator and the external environment. This valve remains closed during normal operation to maintain pressure for rapid deployment, but automatically opens when temperature exceeds a predetermined threshold during fires, allowing pressure relief and preventing device bursting.
Solution Approach 2:
The safety valve's operational state is changed based on temperature parameter. The valve transitions from a closed state (maintaining pressure for rapid response) to an open state (relieving pressure in fire conditions) when the temperature exceeds a predetermined threshold, thus adapting the system's pressure characteristics to different thermal conditions.
2Reliability
If a safety valve is added to prevent bursting in fire conditions, then reliability improves, but device complexity increases
Solution Approach 1:
The safety valve is designed to operate autonomously based on temperature conditions. The valve automatically opens when the predetermined temperature is exceeded during fires, eliminating the need for external control systems, sensors, or actuators. This self-service mechanism adds minimal complexity while ensuring reliable fire safety.
3Reliability
If the gas generator is designed for high pressure to withstand fire conditions, then safety improves, but the device size and weight increase
Solution Approach 1:
Instead of designing the gas generator and housing to withstand extreme fire pressures, a safety valve is introduced as an intermediary pressure relief mechanism. This allows the main device structure to be optimized for normal operating pressures, reducing weight and size, while the valve provides fire condition protection by automatically venting excess pressure.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution ensures high safety for vehicle occupants by preventing gas buildup and potential device bursting, allowing gases to escape during fires while maintaining structural integrity under normal conditions.
Implementation Method 1
The closing ability of the material of the closing element is preferably reduced when the material limit temperature is exceeded, so that the safety valve is released at the latest when gas is applied by the gas generator
Implementation Method 2
an occupant protection device with a pyrotechnic gas generator
Data Source
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AI summary
The invention relates, among other things, to an occupant protection device having a pyrotechnical gas generator (40). According to the invention, a safety valve (200) that operates according to temperature and leads to the outside is connected to the gas generator.